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Failed emissions test


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18 hours ago, rwest said:

This is a warning of what happens when you don't drive a car for 3 years, the petrol additives slowly eat away at the insides of your car :( So far - burst MU diaphragm (replace entire MU), petrol & oil seals on MU drive shaft were brittle and leaking, one of the injector hoses decided to snap, and now the petrol pump. I'll be replacing the petrol filter at the same time. To be fair, the last time I replaced them was about 15 years ago.

Coincidence - I just replaced all the seals in my MU (I was lucky - the two diaphragms appear OK). I last replaced them 20 years ago, and all was well until I took the head off for gas-flowing last year, and the car stood idle for ~3 months. After reinstalling and the head, I kept getting a nasty backfire which no amount of fiddling with timing, PI calibration, butterfly balancing would fix. Finally replaced all seals and 'O' rings, and all is sweet again. Very sweet :)

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2 hours ago, JohnC said:

Coincidence - I just replaced all the seals in my MU (I was lucky - the two diaphragms appear OK). I last replaced them 20 years ago, and all was well until I took the head off for gas-flowing last year, and the car stood idle for ~3 months. After reinstalling and the head, I kept getting a nasty backfire which no amount of fiddling with timing, PI calibration, butterfly balancing would fix. Finally replaced all seals and 'O' rings, and all is sweet again. Very sweet :)

Hi John,

In my experience some your problems are classic if you allow the seals to dry out as there is no petrol to keep them soft. I am surprised that you did not have trouble with the injector seals as they are the usual ones to give trouble after a long lay up? They also go hard!

Bruce.

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2 hours ago, astontr6 said:

Hi John,

In my experience some your problems are classic if you allow the seals to dry out as there is no petrol to keep them soft. I am surprised that you did not have trouble with the injector seals as they are the usual ones to give trouble after a long lay up? They also go hard!

Bruce.

Hi Aston

My injector seals are all suspect as well, I'd already replaced 2 and I've got another 4 are on their way from the UK. There's not much left of my original fuel system now - just a couple of hoses in the boot (which look fine, but I'll probably replace those sometime soon). My car was used almost every day for 20 years with remarkably few issues, but it had to stay in the UK after I moved to France 3 years ago until I could find somewhere to keep it.

Cheers

Robert

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13 hours ago, astontr6 said:

I am surprised that you did not have trouble with the injector seals as they are the usual ones to give trouble after a long lay up? They also go hard!

Hi Bruce,

I agree. If some of the seals have given up then all are suspect. The injectors are working for the moment, but I'm going to change the 'O' rings anyway. The vacuum diaphragm I'm going to leave well alone, and the MU diaphragm seems as soft and pliable as ever (and is a silly price), so likewise. I suspect it's a different material anyway.

John

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  • 3 weeks later...

For anyone following this saga - my car passed the emissions test in the Controle Technique (the French MOT) :D

Also on the positive side, after replacing literally everything between the fuel tank and the injectors (well, including the injectors), the car is running better than it has done for probably 10 years. I haven't tinkered with the MU settings so it is is running very slightly lean (probably good for the emissions test) - maybe when I'm feeling brave enough...

Thanks to everyone with their suggestions, I couldn't have done it without you.

Cheers, Robert

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